1. Field of the Invention
The present invention relates to a deinterlacing apparatus and a method, and more particularly, to a deinterlacing apparatus and a method easily implemented and having a fast process speed, which calculate interpolation values and mixed values for estimated motion vectors, and use selected values as a final interpolation value and mixed value.
2. Description of the Related Art
An interlace scan mode and a progressive scan mode are provided as scan modes of an image display apparatus. The interlace scan mode is employed for general TVs and the like. The interlace scan mode is a mode that, when one image is displayed, divides one image frame into two fields and sequentially and alternately displays the fields on a screen to form an image. At this time, the two fields are referred to as a top field and a bottom field, an upper field and a lower field, an odd field and an even field, or the like.
Furthermore, the progressive scan or a non-interlace scan mode is used for computer monitors, digital TVs, and so on. The non-interlace scan mode is a mode that treats one frame image as a frame unit and displays full frame images at a time like a projecting film on the screen.
A deinterlacing apparatus refers to a device that converts a video signal of the interlace scan mode into a video signal of the progressive scan mode. Video display devices using the progressive scan mode increase in number, and, at the same time, a necessity to exchange data between different scan modes is also increasing, so that the deinterlacing apparatus is required to convert the interlace scan mode to the progressive scan mode.
Diverse methods can be implemented for the deinterlacing or an interpolation method may be used converting the video signal of the interlacing scan mode into the video signal of the progressive scan mode. As a basic method, there is the line replication method replicating line information of a present field to be interpolated. The basic method can be easily implemented, but has a disadvantage that a resolution of the interpolated images falls to a half and a specific image at a specific time can completely disappear.
In order to overcome such a disadvantage, a spatial interpolation method has been developed to implement new fields through a process of inserting an average data of two line data between two lines of a present field, and a temporal interpolation method having no motion compensation but implementing frames by using field lines before and after a present field, between present field lines. Such methods may be implemented in simple hardware, but the methods can generate errors in case of interpolating the images in motion or degrade an image quality due to deteriorations of the interpolated images.
In order to make up for the above disadvantages, the motion-compensated interpolation method has been developed which divides the image into blocks over a continuous field data with reference to a present field data, obtains motions over the respective blocks, and interpolates a present frame image with reference to motion vectors. Such a motion-compensated method is disclosed in U.S. Pat. No. 5,777,682 issued Jul. 7, 1998.
In addition, the motion-adaptive interpolation method estimates an extent of motion and interpolates frames depending upon motions. Such a motion-adaptive interpolation method is disclosed in U.S. Pat. No. 5,027,201 issued Jun. 25, 1991, and U.S. Pat. No. 5,159,451 issued Oct. 27, 1992, and so on.
However, the motion-adaptive interpolation method is relatively simple in a hardware structure so that the motion-adaptive interpolation method can be easily implemented at less cost, but has a problem of deteriorating the performance for image quality improvements. Further, the motion-compensated interpolation method requires a large number of pixel data from a current to-be-interpolated field and reference fields for motion estimations, so the motion-compensated interpolation method needs to access massive amounts of data from a field or frame memory or to store data in a buffer of large capacity, which makes implementations complicated and the implementation cost high.
Further, the motion-compensated interpolation method generally uses unit block motion vectors for the motion estimations and compensations, so that, because error corrections are carried out for every block unit, a block artifact occurs on interpolated images from time to time. Accordingly, a subsequent process to prevent the artifact is needed, which brings out a problem of making an overall hardware structure considerably complicated.